A better roof (possibly with a rain water purification system)

I have an idea I want to share to create a non-toxic, food-grade roof, since we need a new roof for our modest Portland Oregon home.  I want to replace my aging roof with shingles made of a non-toxic food grade material to provide clean rainwater for watering my edible landscape, and possibly for emergency drinking.  My current patch-job asphalt roof is made of petro-chemicals, which flake off into my rain barrels, which then is used to water my edible plants.  The roofers, builders, and rain barrel sellers I’ve talked to say there is no such thing as a non-toxic food-grade roofing material that is reasonably priced and would work on my home*.  I’m looking for a product already in use possibly elsewhere in the world, or a company willing to invent/sell a food-grade roofing product for a reasonable price.

Why are roofs made that pollute clean rainwater? Everyone living in a house, apartment, or trailer has a ROOF. If we had non-toxic food grade roofs, we could rest assured rainwater stored in our rain barrels and run-off on plants wouldn’t be leaching toxic chemicals into our soil – since the roof itself won’t be leaching toxic chemicals into our rainwater. Also, with fresh water getting scarcer worldwide, it makes sense to utilize at least some of our free rainwater for emergency back-up, thus taking some of the load off community water sources during emergencies.

Needed:

1.  Food grade roofing shingles in the same size/heft/price as traditional asphalt shingles so they can be easily and conveniently installed by roofing companies.
2. Food-grade roofing materials might include a combination of food-grade plastics (Our rain collection barrels are a food-grade plastic that formerly stored pickles), retired solar panels, or food grade flexible silicon currently used in measuring cups and potholders – combined in such a way as to make a flexible yet waterproof material similar in size/weight as an asphalt shingle.  Other food-grade options might include food-grade and waterproof materials used in cooking pots and ovens.   Possibly barley straw might somehow be utilized as a water purifier or some combination of natural alkalizing rock as possible additions to the shingle, rain barrel, or gutter to help neutralize acid rain in the rain water in areas where coal is burned.
3. People who have hands-on experience with commercial passive solar ovens/passive water purifiers (such as Sun Ovens) might be willing to design simple and safe emergency UV water purification systems that would work with rainbarrels for home use.
4. People who have hands-on experience with passive filtration for rain barrels might be willing to sell/package a barley straw/alkalizing rock addition to rain barrels, or some sort of layering of materials including silver to kill pathogens as well as the appropriate sand, rocks, etc, at a reasonable price. High tech, low tech, and/or practical tech. Third world country wisdom appreciated to help apply these principles to roofing systems worldwide, especially where drinking water is scarce.

*Current roofing materials available in America:

• Asphalt:  Loaded with petro chemicals that off-gas toxic fumes. As roofing material breaks down over the years, petrochemicals and toxins flake off into the rainwater, thus polluting the ground soil it falls upon.  If this ground soil is used for edible landscaping (as mine is) the accumulated toxins from years of toxic chemical flake off could compromise my food – and my health.
• Metal: When I’ve asked for a non-toxic roof option, Metal roofs have been suggested by local roofers.  However, metal roofs are coated with chemicals so they don’t rust.  These chemicals are toxic, and as the roof ages, they flake off into the water/soil as well.  Plus, they need to be re-painted/re-coated with MORE toxic chemicals when that happens, or the roof will rust.
• Green Roof: used on flat or near flat surfaces due to soil and plants. Most family homes don’t have the infrastructure to support the added plant/soil weight, and most family roofs are pitched, not flat.
•  Tile and slate: expensive to purchase, expensive to install, too heavy for most average and smaller homes infrastructure.  There’s a new technology called TruSlate that uses smaller tiles and therefore is lighter so it may work for new homes/remodels. TruSlate costs about 1/3 less than traditional slate but takes about a week to install so is labor intensive and still quite expensive.
•  Cedar: Originally, Oregon Cedar was used since as a native plant it was naturally waterproof for Oregon houses.  However, now all cedar shingles are imported and the cedar isn’t waterproof…so it is treated with toxic chemicals soaked into the wood.  These chemicals then leach into the rainwater and into the soil.  This is also an expensive option to have installed, and many insurance companies frown on cedar roofs because as they age they become a fire hazard.
•  Recycled Tires/’Rubber’ Roofs: From what I’ve read, an intact tire at the bottom of a lake is generally stable.  However, when used tires are shredded to form Rubber Roofs, they from that point on release their toxic chemicals in the air and water.
•   Copper:  When you want to keep slugs out of your yard, you put a copper barrier around what you want to protect.  Copper has an electrical charge that isn’t healthy for wildlife or people. Rainwater from copper roofs contains lead, according to this article. Also from the article: Rainwater from copper roofs contains lead. Rainwater from cedar shake roofs contains antimicrobial and wood preservatives. Asphalt roofs leach polyaromatic hydrocarbons and phthalate esters. The concentrations are small but no safety standards currently exist in the US.

What I need is a simple, affordable, non-toxic roofing shingle in a familiar form that every installer already knows how to use so installation costs stay low.  A shingle the same approx weight/heft/size as an asphalt roofing shingle, but made with materials that don’t pollute water, air, and soil.

As an additional bonus, it would be great if there was also a water barrel system or gutter system where rainwater could be stored and kept relatively safe and clean, so in an emergency water could be put into a solar oven with UV purifiers to create emergency potable water for washing dishes, sponge bathing, etc.

I entered this idea in the 2012 Nissan Innovation Garage contest.  My wish is for thought leaders/doers  in industry to see the practicality, sustainability, as well as easy market acceptance (heck, we’ll help you with audio marketing tools/copywriting), to create a non-toxic roofing shingle.  Or if you know of a roofing shingle that is already available, PLEASE let me know where I can purchase it – because I need a new roof!

Original idea by Barb Hughes